During the processing of photographic materials, one or more rinsing steps may be used to remove residual processing solution from the materials prior to contact with the next processing solution. Moreover, before processed materials are dried, they are generally rinsed a last time to remove all remaining chemical residues so that when they are dried, they are free of lines, water spots or scum. For example, in processing most films and papers (both color and black and white), a final rinsing or stabilizing step is used prior to drying. This is the case for motion picture films as well. In fact, because of the stringent processing conditions and requirements, motion picture films may require several washings prior to drying.
Many different formulations have been proposed for use as rinse solutions in photographic processes. Generally, they include one or more surfactants that facilitate the "cleaning" of the photographic material and uniform liquid drainage. Some final processing solutions also contain dye image stabilizers and are thusly known as stabilizing solutions. In addition, rinse or stabilizing solutions can contain one or more biocides to prevent unwanted biological growth in the processing tank or on the photographic material. The solutions may additionally contain calcium ion sequestering agents or polymers such as polyvinyl alcohol to reduce precipitation of sulfur or sulfides.
To meet all of the needs of a rinse solution, especially a final rinse solution, a careful formulation of components, generally surfactants and biocides, must be made. Proper balancing is required to keep costs low, minimize foaming and biological growth, while achieving the desired drainage and defect free processing expected by highly critical customers.
Not every rinse solution useful for processing one type of photographic element may be useful for processing other types of elements. Each type of photographic element may have surface characteristics, or be processed using unique chemicals that require unique rinse solution components. In addition, there is generally a desire to inhibit biocidal growth in such rinse solutions and on the processed elements themselves. This usually requires the presence of a biocide in addition to surfactants necessary for residue removal.
A conventional final rinse solution for processing color motion picture films includes a nonionic surfactant such as tridecylpolyethyleneoxide (12) alcohol, commercially available as RENEX 30 from ICI Surfactants. It has been observed, however, that such solutions exhibit a continual problem with biological growth, requiring frequent changes in solution and cleaning of the processing tanks. In addition, antimicrobial agents may be added, but such compounds must be handled carefully because of potential eye and skin irritation.
Thus, there is a continued need in the art for an improved, low cost, effective and non-irritating photographic rinse solution that achieves all of the desired results with minimal chemicals.